Harvey Two-Face Dent is a fictional supervillain appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman. The character was created by Bob Kane and Bill Finger, and first appeared in Detective Comics #66 (Aug. 1942).
reactivity. 1  the quality or condition of being reactive. 2  Chemistry. the relative capacity of an atom, molecule, or radical to undergo a chemical reaction with another atom, molecule, or compound. 3  Physics. a measure of the deviation from the condition at which a nuclear reactor is critical.
Reactivity of a gas is a classification as to whether or not it will chemically react with the molten weld puddle. Gases can be divided into two groups, inert and active. Inert gases, or noble gases, are those that are unreactive with other elements in the weld puddle. Argon is an inert gas.